Connectivity is becoming more and more important, with establishing and maintaining a connection at low power being the objective. In this installment of Deep Green, we review a GPS receiver, a new class of DIMM modules, and a Continua Certified USB implementation helping medical devices connect efficiently.

GPS engines match power to need

Adding GPS to a device is nice, but it can be a power hog. Looking at use cases for GPS reveals a number of trade-offs that can balance accuracy, speed of location fix, sensitivity, and power to extend a device’s battery life. Atheros Communications has addressed this need with the FYX location core and software in the third-generation AR1520 GPS receiver.

Figure 1: AR1520 GPS receiver

The FYX location core comprises eight hardware-based search engines coupled to 16 dedicated tracking engines, which can run separately for quicker reacquisition times or work together for faster start-up searches, shutting down in stages to save power when a fix is made. The engines are optimized to keep track of even weak signals in multipath situations like urban canyons.

The results are impressive – the AR1520 claims high-accuracy GPS tracking at less than 30 mW, low-power tracking at less than 10 mW, and an AlwaysReady mode for “hot start” consumption at less than 1 mW.

Isolation memory buffers reduce power

Memory capacity and bandwidth needs are always going up, but servers are being pushed to decrease power consumption even as these performance factors increase. JEDEC has established a new specification for an isolation memory buffer that replaces a traditional register, creating a new class of devices called Load-Reduced Dual-Inline Memory Module (LRDIMMs).

Figure 2: iMB02-GS01

Inphi’s new iMB02-GS01 isolation memory buffer enables more ranks of DRAM to be populated on a memory module. On most usage models, Inphi claims that a quad-ranked LRDIMM consumes lower power in both active and idle conditions compared to an equivalent quad-ranked RDIMM with the same capacity. This overall reduction in power consumption is brought about by improved termination power optimization on the LRDIMM.

Continua Certified USB agent stack

In previous coverage of the Continua Health Alliance, we heard about the benefits of connected devices in health care. One of the methods the group is focused on is USB. While many microcontrollers can provide a USB connection, a Continua Certified USB agent stack is needed to ensure interoperability of the device at work, such as a blood glucose meter, digital thermometer, pulse oximeter, or blood pressure monitor.

Figure 3: Embedded Agent Stack

S3 Group has announced availability of the first Continua Certified USB-enabled platform in the form of the Embedded Agent Stack (EAS). EAS is an ISO/IEEE 11073-compliant PAN device (agent) stack. The standard defines how to exchange and evaluate vital signs data between point-of-care devices. The EAS implementation is optimized for resource-constrained platforms such as ultra-low-power MCUs like TI’s MSP430.